This invention relates to a process for homogenizing a compound semiconductor single crystal in various properties such as electrical, electronic and optical properties.
Semiconductor substrate crystals produced by a liquid encapsulated Gzochralski (LEC) method or a horizontal Bridgman method usually have various properties such as electrical properties heterogenously distributed in (100) plane used in integrated circuits. In order to homogenize these properties, there have been proposed various processes.
For example, in the case of a gallium arsenide (GaAs) single crystal, since arsenic (As) is released from the surface of an ingot or wafer, a heat treatment is carried out in an arsenic atmosphere in order to prevent the release of the arsenic (e.g. Japanese Journal of Applied Physics vol. 8, No. 8, p. 1000, 1969). But, according to this process, it is difficult to control the arsenic pressure and to handle poisons.